In recent years, global warming issues have created much debate. Central governments, companies, and consumers are recognizing the importance of the environment and the movement to reduce CO2 gas emission is becoming stronger in its advocacy against increased energy consumption. In addition, policies to promote the generation of low amounts of carbon in the environment, such as eco-point awarding systems that promote the replacement of high energy consumption units with energy saving units, and anti-global warming tax are being implemented. Moreover, in the future, conversion of actual electric power consumption into economic values, such as eco-points that are awarded based upon the difference in the amount of power consumed by products, and the imposition of a carbon tax on poor energy efficient devices may be implemented not only at the time of product purchase, but also when the product is being used.
It is important to accelerate the reduction of the electric power consumption especially for electric devices that consume large amounts of electric power such as air conditioners, refrigerators, large TV receivers (hereinafter abbreviated as TVs), and IH (Induction Heating) cooking heaters. If consumers, employers and so forth are able to easily check the amount of electric power that such electric devices consume, the expectation is that these units will save energy while operating and save energy throughout their product lifecycle.
However, in order to measure the amount of electric power that is consumed by electric devices so that this can be accurately billed of converted into economic values, these electric devices need to be measured by government certified electric power meters in accordance with the Measurement Law of Japan. In addition, in order to find out the result that measures the amount of electric power that has been consumed, the user needs to check the utility bill that has been sent from the power company of needs to obtain this information on the company's website.
Of course, the amount of electric power consumed by individual electric devices may be measured by government certified electric power meters in accordance with the Measurement Law. However, if such electric power meters are provided to individual electric devices, since the size of the electric devices are large and the cost of the electric devices rises, it is difficult to use such electric power meters. Even if such electric power meters are used, it is difficult to know the measurement results of individual electric power meters easily in real time.
However, thus far, many techniques that measure electrical power consumption of devices that are used in households, but that cannot convert the measurements into economic values, have been proposed. These electric power measurement techniques according to the related art can be roughly categorized into two groups.
(1) Non-intrusive technique: Current sensors or electric power sensors are provided at branch circuits or the like of a home distribution switchboard. The total amount of electric power consumed by electric devices connected to the branch circuits is measured corresponding to the measurement data of the sensors (for example, refer to Patent Literature 1).
(2) Intrusive technique: A current sensor or electric power sensor is directly installed in an electric device or placed between the plug of the electric device and a power outlet (if a clump type sensor is used, the power cable is clumped by the sensor) so as to measure the amount of electric power consumed by each electric device (for example, refer to Patent Literature 2).
Patent Literature 1 presents a technique in which storage means stores power factor information and rated voltage information of individual electric devices, current sensors are provided at individual branch circuits of the distribution switchboard, and the amount of electric power consumed at each branch circuit is estimated corresponding to information of the current sensors and information of individual electric devices connected to the branch circuits provided with the current sensors. Patent Literature 2 presents a technique in which individual electric devices are provided with unit adaptors that obtain the amount of electric power that is consumed and unit information of the individual electric devices.
As described above, the electric power measurement systems, according to the related art, cannot accurately convert power consumption measurements into economic values, unlike government certified electric power meters that measure the amount of electric power consumed by individual electric devices according to the Measurement Law. Thus, the problem exists in which measurement accuracies based upon these techniques are poor.
Even if electric power meters that are government certified according to the Measurement Law are provided to individual electric devices, it is difficult to easily know the amount of electric power that is consumed by each electric device in real time.
In addition, it is difficult to know the amount of electric power generated by electric power generators such as solar batteries and charging/discharging power of secondary batteries that are being implemented to achieve a low carbon emission environment.
In other words, there is a problem in which the electric power measurement systems according to the related art cannot easily measure electric power such as the amount of electric power consumed by electric devices, the amount of electric power that is generated, and the amount of electric power used to charge/discharge various types of electric devices by individual users in real time and to accurately convert these measurements into economic values.